SpringBoot 自定义拦截器 - 解决登录验证

需求：只有登录了才能访问URL,需要验证当前是否处于登录状态。这里通过判断session中是否存在用户信息。

1.自定义拦截器：登录验证

package com.ming.boot.intercepertor;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 自定义拦截器：登录检查
 * 1.配置好拦截器要拦截哪些请求
 * 2.把这些配置放在容器中
 */
@Slf4j
@Component
public class LoginInterceptor implements HandlerInterceptor {

    /**
     * 目标方法执行之前
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        String requestURI = request.getRequestURI();
        log.info("拦截的请求路径：{}",requestURI);

        //登录检查逻辑
        HttpSession session = request.getSession();
        Object loginUser = session.getAttribute("loginUser");
        if(loginUser != null){
            //放行
            return true;
        }
        //拦截。未登录，跳转到登录页
        request.setAttribute("msg","请先登录");
//        response.sendRedirect("/");
        request.getRequestDispatcher("/").forward(request,response);
        return false;
    }

    /**
     * 目标方法完成执行之后
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        log.info("postHandle执行了：{}",modelAndView);
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    /**
     * 页面渲染之后执行
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        log.info("afterCompletion执行的异常：{}",ex);
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

2.SpringBoot 注册自定义拦截器，并设置拦截的请求

package com.ming.boot.config;

import com.ming.boot.intercepertor.LoginInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Autowired
    private LoginInterceptor loginInterceptor;

    /**
     * addPathPatterns 添加拦截的请求， /** 拦截所有请求(包括静态资源)
     * excludePathPatterns 放行哪些请求(不拦截)
     * @param registry
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(loginInterceptor)
                .addPathPatterns("/**")
                .excludePathPatterns("/","/login","/css/**","/fonts/**","/images/**","/js/**");
    }
}

注意在自定义拦截器上加上注解@Component，在注册拦截器时加上注解@Configuration